Multiple choke switch mechanism



Aug. 4, 1959 L. J. BISHOP ET AL MULTIPLE CHOKE SWITCH MECHANISM 4 Sheets-Sheet 1 Filed Nov. 6, 1957 INVENTORJ Aug. 4, 1959 Filed Nov. 6, 1957 L. J. BISHOP ET AL MULTIPLE CHOKE. SWITCH MECHANISM 4 Sheets-Sheet 2 I l l x 1. 'I

L. J. BISHOP ET AL MULTIPLE CHOKE SWITCH MECHANISM Aug. 4, 1959 4 Sheets-Sheet 3 Filed Nov. 6, 1957 INVENTORS A folk 4R0 d. BIS/lop Aug. 4, 1959 L. J. BISHOP ET AL MULTIPLE CHOKE SWITCH MECHANISM 4 Sheets-Sheet 4 Filed Nov. 6, 1957 United States Patent MULTIPLE CHOKE SWITCH MECHANISM LeonardJ. Bishop and Robert Haase, Birmingham, Mich., assignors to Mechanical Handling Systems, Inc., De troit, Mich., a corporation of Michigan Application November '6, 1957, Serial N 0. 694,865

15 Claims. (Cl. 104-88) The present invention relates to an improved mechanical switch mechanism for an industrial or like conveyor system, for example, of the type illustrated and described in the copending application of Paul Klamp, Serial No. 601,001, filed July 30, 1956, now 'Patent No. 2,868,139, Jan. 13, 1959. The conveyor system of that application is an overhead one of the monorail, so-called power and free. type; however, it is to be understood that the improvement of the present invention, dealing in particular with a multiple switch choke and object accumulating "operation, is by no means limited in its application to an overhead conveyor.

It is an object of the invention to provide a switch mechanism by which traveling objects, such for example as trolley type load carriers, may be selectively diverted from a main conveyor reach onto a side or branch reach merging therewith at a switching zone, which mechanism has'a switch controlled for the accumulation of a plurality of diverted objects at an accumulation or equivalent station on the branch reach. In accordance with the .improvement insurance is had that '(a) there will always be two or more objects at the accumulation station while the switch remains in a straight-through non-diverting position, aliording adequate accumulated work for operators; and (b) there will always be suflicient room at the accumulation station, when the switch is in switching position, "to accommodate two objects diverted toward the same.

In attaining this object the switch mechanism is controlled mechanically by object-tripped signal devices respectively located at the advance, main track side of the switch and at its rear or retreating, branch side, as in the prior copending Klamp application; and as in that application theswitch "is latched by a plural phase control device to hold it in a non-diverting position, despite an advance signal *from an approaching object which would otherwise condition the switch for diversion.

However, in accordance with the present invention, movement of the switch to diverting position is deferred, under the control of an improved multiple choke unit, so long as there are a predetermined plurality of objects at the accumulation station.

Further, the switch is automatically unchoked in responseto a multi-p'hase signal originated by a plurality of previously diverted objects, so as to admit and accumulate a pair of advancing and signaling objects, only when previously accumulated objects depart from the station and its occupants fall below the desired number. It is in this sense that the control means of the invention performs what is referred to as a multiple choke action on the switch.

it is another object to provide an automatic, multiple choke switch mechanism of this character which is entirely mechanical in its composition and operation, being entirely unreliant upon electrical, hydraulic and pneumatic controls, suchasaddgreatly to the'cost of production and -'i-nstallation, yet impose continuous demands in regard to inspection, servicing and other upkeep.

A further object is to provide a multiple choke switch mechanism, comprising a single phase signaling device or unit disposed in advance of a mechanical switch tongue, a further, multiple phase signaling device at an accumulator station on the departing or branch reach, and a step-wise acting switch choke or control device operating in a novel way in mechanical response to the signaling devices. The operation of the control device, assuming a maximum required number of objects are at the branch station, is to fully choke the switch in its straight-through position until two objects have moved along that station, signaling at the multi-phase device as they move. The next advance signal will release the switch for movement to diverting position, and the return of the switch to choked, straightthrough position takes place after another object signals from the accumulation station. Should two such signals occur, the switch again remains choked until two -advancing objects are switched.

The arrangement and operation in a switch of this type are such that mechanical signals from the advance signal station will cause the multiple choke control unit to repeatedly condition the switch, tentatively, to be placed in an object diverting position; but the connection of the unit tothe muliple phase signaling unit will prevent such posi tioning so long as there area plurality of objects at the last named station.

A still further object is to provide asystem as described in which the switch is restored or reset'by a switched object from its unchoked position to a position for choking.

More particularly, with regard to structure, an object is to provide a multiple choke switch mechanism, in which the switch includes a switch tongue and control we tension connected thereto by a resiliently biased, lost mo tion connection; in which a primary mechanical latch con- .trol arm is recurrently actuated mechanically by a signal ing object at the advance signal station, moving between operative engaging and release positions relative to the extension; in which .the control means for the switch further comprises an arcuately faced latch surface choked and unchoked in progressive mechanical phases by a latch arm responsive to signals from the branch accumulating station; and in which the last named station comprises .a series of similar signal units mechanically linked to one another, as well as to the last named latch arm.

In general, it is an object to provide an all-mechanical control performing a multiple phase switch choking and reversible switch unchoking and releasing operation of the character described above, which control is extremely simple and uncomplicated as to its :parts, compact, readily installed, inspected and serviced, yet very rugged and well suited to withstand the rough treatment to which it is subphysical relationship of a primary latch device for the switch of Fig. '1 to an "advance signaling station or unit;

Fig. 3 is a fragmentary view in vertical section and enlarged scale along broken line 3-3 of Fig. 1;

Fig. 4 is a fragmentary elevation, with non-essential track provisions broken away, along a line corresponding to line 44 of Fig. 1;

Fig. 5 is a fragmentary elevational view of a signaling unit of a multi-phase signal device associated with the switch of Fig. '1;

Figs. 6 and 7 are, respectively, fragmentary views in vertical transverse section along the lines 66 and 77 of Fig.

Fig. '8 is a schematic view in elevation of the multiphase signaling device constituted by units in accordance with Figs. 5, 6 and 7, showing the device in relation to an accumulator station and an article at the station;

Fig. 9 is an end elevation, as from line 9-9 of Fig. 2, of a primary latch unit associated with the switch of Fig. 1;

Fig. 10 is an end elevation of an advance signaling device or unit operatively connected with the latch unit of Fig. 9, being as viewed from line 1010 of Fig. 2;

Fig. 11 is a fragmentary and schematic plan view showing in solid and dotted line a switch reset arrangement and its operation; and

Fig. 12 is a vertical section illustrating the type of trolley transported object controlled by the switch mechanism of the invention.

The switch mechanism of the invention, generally designated 10, is best shown in Figs. 1, 3 and 4, and is of the same general type as that constituting the subject matter of the above identified Klamp application. Its parts are shown in solid line in Fig. 1, in which an overhead, load bearing trolley T, of the type depicted in Fig. 12, passes undiverted by the mechanism along what may be termed a main overhead track reach 11. The said parts are shown in dotted line in their operative position, in which a trolley T is switched onto an adjoining curved connector portion 12 of a branch track reach 13, all as described in detail in the Klamp application.

In view of the fact that the present invention deals solely with an improved multiple phase, multiple switch choke control for the accumulation and maintenance of plural article carrier or like objects on the branch track portion 13, it is deemed sufiicient to make only brief reference to parts, arrangement and relationships shown and more fully described in the Klamp application.

Such components comprise a switch tongue or frog 15 pinned to and journaled by an upright pivot pin 16 (Fig. 3) in upper and lower ball bearings 17 in a generally triangular tongue mounting member 18, which member coacts with the respective main and branch connecting track sections 11, 12, in defining the main and branch track openings 19, 20. Guide rollers 21, by which track trolleys T of the type shown in the Klamp application are guided in the respective track openings 19, 20, are shown in Fig. 12 and indicated in dot-dash line in Fig. 1.

Referring to Fig. 12, the trolley T is advanced by an overhead power chain and power trolleys P thereon which releasably engage the trolleys T in a well known manner. In similarly known manner, the trolleys T sustain load supports equipped with rectangular bumpers B, and each of these bumpers is equipped, midway of its front-rear length and adjacent a side thereof, with an upright switch reset actuator roller 22, as indicated in Figs. 6, l0 and 11.

The switch tongue 15 is provided with a rigidly connected rear extension arm 23 and the extension has its rear extremity slotted at 24. A secondary, lost motion tongue lever 25 is pivoted on the rear tongue arm 23 by an upright pin 26 and associated bushing means 27, this secondary lever acting as a latch arm for the tongue 15, and to that end being of a special outline, as will be described. It has a depending lug 28 which is received within the rear slot 24 of the tongue extension 23, and coil springs 29 act between the lug 28 and the opposite side surfaces of slot 24 to aiford a resilient lost motion connection between the primary switch tongue 15 and the secondary lever 25. The pumose of this lost motion provision is to maintain the advance end of tongue 15 snugly against either the main track section 11 or the branch track section 12, in the respective diverting (dotted line) and straight-through (solid line) positions of the tongue, for reasons to be described.

Secondary lever 25 is equipped with an angled, downwardly offset reset tail 31 which swings beneath the track section 13 (Fig. 4) and is adapted to be engaged by the actuator roller 22 on a bumper B, thus enabling the tongue 15 and its secondary lever 25 to be swung clockwise, as shown in Fig. 11, about the main pivot 16 by a switched trolley T, thereby to reset the tongue structure to its straight-through position, in which it is latched by the means now to be described.

Intermediate its length, the tongues secondary lever 25 is provided on its upper surface with a fixed latch seat or abutment 33, and this abutment serves as an anchor member on the tongue lever for a strong coil power spring 34 of the switch, its other end being anchored by a pin 35 on the fixed tongue mount 18.

The latch abutment 33 is provided with an outwardly concave arcuate seat 36 adapted to be engaged by a roller 37 on the primary latch arm 38; and this arm is appropriately pivoted by an upright shaft 39 in a vertical elongated tubular bearing member or sleeve 40 sustained by appropriate fixed superstructure parts of the installation. A coil spring 41 is connected to arm 38 at 41 and is anchored at its opposite end 41 to a fixed pipe or other frame or superstructure part, Thus latch arm 38 is biased counterclockwise in a direction to be engaged with latch abutment seat 36. Swing of the arm 38 is limited by any suitable means.

It is in order at this point to refer to Fig. 2 of the drawings for a general disclosure of a mechanical operating connection between the pivoted latch arm 38, and an advance signaling station, device or unit 42 adjacent the main track section 11, in advance of the switch 10. In this connection, reference may also be made to Figs. 9 and 10 for a suggested structural arrangement of the latch arm and the operating connection referred to. As shown in Fig. 9, the pivot shaft 39 of the latch arm 38 extends upwardly through the sleeve bearing 40, above which it has fixed to it a laterally projecting trip lever 43. This lever is pivotally connected through an elongated link 44 to the advance signal unit 22, the link extending forwardly or in the direction from which carriers or other objects, such as the trolley-borne bumpers B, advance.

The link 44 is pivotally connected to a laterally projecting arm 45 of the signal unit 42, reference being now had to Fig. 10, and the arm 45 is fixed to a depending pivot rod 46 journaled in an upright bearing sleeve 47, shown as typically sustained by parts 48 of the superstructure of the installation. Downwardly of bearing member 47, the pivot rod 46 fixedly carries a signal arm or trip lever 49, which extends laterally into the path of movement of a selectively settable flag 50, the flag 50 being adjustably positionable vertically, in a known way, upon a bumper B or like article carrier advancing on track section 11 toward the switch unit 10. A further flap or flags 52 may be similarly employed in signaling switch units other than the controlled unit 10 herein shown.

The reference numeral 48 in Figs. 9 and 10 designates suitable superstructure provisions of an entirely conventional character, for assisting in the fixed mount of the sleeves or hearing members 40, 47, on the equipment. The invention is not concerned with such details, particularly since as indicated above the principles of the invention are not limited in application to an overhead installation.

As illustrated in Fig. 2, a continuous chain 55, appropriately trained about end sprockets 56 in an arcuate path concentric with the outline of the connecting track section 12, may be provided to assist the travel trolleys T and bumpers B in passing onto the branch track 13. Although this insures a power resetting of the switch reset tail 31 by the bumper actuator roller 22, the invention does not concern itself with provisions of this sort, which are also shown in the copending Klamp application. It is preferred to reset the switch by a roller on the bumper, rather than by a guide roller of the trolley, as in that disclosure.

The multiple phase, choke control of the switch unit I is accomplished by the action of the advance signal unit 42, in controlling primary latch arm 38, in conjunction with the further timing action exerted upon the tongue unit 10 by the multiple phase branch signaling station or unit which is generally designated 58 in Fig. 8. Signaling unit 58 is located to extend along what may be termed an accumulating station or zone extending, for example, the distance Z along the branch track 13, to one side of the latter.

For its augmented control by the accumulator signaling unit 58, the switch unit 10 is provided with a secondary latch device (Figs. 1, 4 and 11) in the form of a fixed extension on its secondary, lost motion lever 25, in addition to the reset arm 31 carried by that lever. The latch device comprises a horizontally extending plate 59 of generally L-shaped outline, including a mildly arcuate, forwardly or inwardly concave latch face 60 and an outwardly disposed, mildly convex holding face 61 formed on an offset 62 of thesecondary latch plate 59.

As depicted in Fig. 1, an appropriate part of the track supporting structure has a bracket 64 bolted thereto, the bracket presenting a laterally projecting lug or nose receiving an upright pivot pin 65. Pin 65 pivotally mounts one arm of a bell crank-shaped member 66, theapex of which journals a secondary latch roller 67.

An inoperative, switch release position of the latch roller 67 is shown in solid line in Fig. 1, and three successive alternative positions thereof are shown in dotted line in that figure, being respectively designated I, II and III. It will be noted that in the solid line position and the next adjacent dotted line position I the roller 67 is located so as not to be abuttingly and latchingly engaged by the arcuate latch face 60 of the latch plate 59. It is then in a position in which the holding face 61 of the plate 59 will pass by roller 67 as the plate swings counterclockwise from the solid line, straight-through position of the parts to the dotted line, switching position thereof. In both of the other two dotted line, latching positions II and III of the'latch roller 67 it is engaged by the latch face 68. Thus roller 67 holds the switch structure (single choke position II or full choke position III) against the pivoted unlatching movement just referred to; and this is so regardless of repeated signalings at the advance signal station 42 having the effect of repeatedly conditioning the primary latch arm 38 for a release of the primary latch abutment 33 and the switch 10.

Referring now to Figs. through 8 in conjunction with what is shown in Fig. 1, the multi-phase, branch track signaling unit 58 includes a series of articulated push-pull links or rods 70 and interspersed signaling devices 71 (hereinafter described). The endmost righthand rod 70 (Fig. 1) is operatively connected to an adjacent arm of the bell crank latch member 66 through'the agency of a swivel eye 73 on the latter, which slidably receives a headed outer end 74 of the rod 70. A coil compression 75 acts between the eye 73 and a stop collar 76 fixed on the rod 70, thus cushioning a push operation of the link 70 should it take place for any reason when the latch plate 59 is in a released, dotted line position (Fig. 1).

' Referring now to Figs. 5, 6 and 7, each of the signal devices 71 comprises a fixedly mounted horizontal guide 77 providing a laterally restraining horizontal guide way 78, in which a first slide plate 79 has sliding motion. Intermediate its length, plate 79 has a pivot member 80 projecting from a side thereof, on which a special actuating cam 81 is journaled, and the cam 81 has a radial operating arm 82 extending therefrom and equipped with an anti-friction roller 83. This roller is located relative to the branch track 13 so as to be engaged and swung from solid line to dotted line position (Figs. 5 and 8) by trolley-borne-bumpers B diverted by switch unit 10 onto .the branch track, along which they pass to the accumulator station Z. Rollers 83 ride the top surface of the bumper, along one side thereof.

Cam 81 is normally urged to the inoperative, solid line position of Fig. 5 by a coil spring 83 acting between the same and an anchor pin 84 on slide plate 79.

Slide plate 79, to the right of cam 81 as viewed in Fig. 5, has fixed thereon a further or auxiliary, horizontally slotted guide or way 85, in which a cam follower roller 86 is slidably guided. Follower roller 86 is journaled on a slide link 87, to the righthand end of which a pushpull rod 70 is pivotally connected.

The central signal device 71 shown in Fig. 8 has its slide link 87 pivoted through a push-pull rod 70 to the slide plate 79 of the right hand device 71; and it has its own slide plate 79 pivotally connected through a rod 70 with the slide link 87 of the left hand signal device. The slide plate 79 of the left hand device 71 is fixedly anchored at 89.

This completes the structure of the individual signal devices 71 constituting the signal unit 58, and it will be observed that in each case an object-actuated swing of the cam 81 in clockwise direction (per Figs. 5 and 8), will cause the cam face 88 on cam 81, in engaging follower roller 86, to shift its slide link 87 a predetermined distance to the right. A corresponding shift of the rod 70 takes place with a shift of the bell crank member 66 (Fig. 1) and a predetermined clockwise movement of the latch roller 67, as from the solid line position to dotted line position I. Reverse swing of cam 81 occasions similar indexing movement to the left.

With reference to Fig. 8, there are in the illustrated embodiment three of the signal devices 71, which are identical and operate identically, save for the fact that the slide plate 79 of the endmost device to the left (Fig. 7) is fixedly anchored at 89.

In each instance, a tripping of the cam actuating roller 83 by a switched object arriving at a device 71 will shift its associated push-pull rod 70 to the right a distance of one inch, in a typical installation. In such a typical installation, with reference now to Fig. 1, it requires a total shift of three inches to the right of the latch roller 67, i.e., three cam actuations of signal device 58, to bring the latch roller 67 into full choking engagement (position III) forwardly of the face 68 of the latch plate 59.

In its solid line position of Fig. 1, as well as its initially shifted position I, the roller 67 is incapable of latching the plate 59. Hence, upon the next initiation of a signal at the advance signaling station 42, resulting in a re moval of the primary latch roller 37 from position before latch abutment 33, the switch tongue 15 is urged by power spring 34 to its dotted line switching position, conditioning a switch unit 10 to divert an advancing trolley into the arcuate connecting track reach 12. By the same token, when roller 67 is in full choke position III it will take two indexings of it to the left to unchoke the switch.

As trolleys T are diverted, they pass along switch track section 12, each resetting the switch tongue 10 to its solid line position, by causing bumper roller 22 to engage the reset tail or arm 31, in which position the tongue will be latched by the primary and secondary latch rollers 37 and 67 if circumstances warrant.

It will be noted by reference to Fig. 8, that the length of the bumper B is such that it can engage and hold any two successive signal actuator rollers 83 in their operated positions, i.e., to swing the associated cam 81 clockwise.

In operation, assuming that the switch tongue 15 is latched, by primary roller 37 alone, in the straightthrough, solid line position of Fig. 1, that branch signal station Z is unoccupied, and that the multiple choke latch roller 67 is in the inoperative, solid line position of Fig. 1, a first selected carrier or bumper B approaching the advance signal station 42 will trip the actuating arm, 49 of the latter by engagement of its pre-set bumper flag 50. This motion is transmitted through the linkage comprised of arm 45, link 44 and arm 42 to the primary latch arm 38, thereby swinging primary latch roller 37 clockwise out of retaining engagement with the latch abutment 33.

Power spring 34 now snaps tongue 15 to the dotted line position, and the carrier which initiated the signal proceeds into the branch track section 13, its reset roller 21 resetting the tongue 15 to solid line position, as explained above.

A second advancing carrier having its flag 50 similarly set initiates a second similar signal at unit 42., with a similar opening of tongue 15 to switching position, then a resetting of it by reset arm 31.

These carriers are then advanced into the branch track by means of the actuator chain 55 (Fig. 2), or manually if such device is lacking. The first-admitted carrier now trips the first of the multiple phase signaling devices 71, Le, the one to the right of Fig. 8, causing a first indexing, through its push-pull rod 70 of the latch roller 67, La, from its solid to its dotted line position I. This still leaves that roller in an inoperative position in which it is incapable of latching the tongue 10.

A third carrier or bumper B is admitted into the branch track section 13 by a similar, single phase signaling at advance signal unit 42, and as the first, second and third carriers are advanced towards and into the accumulation station Z the secondary latch roller 67 is successively indexed into its dotted line positions II and III.

The switch unit 10 is now multiple choked, in that it will take two successive reverse indexing movements of the latch roller 67, Le, to the left in Fig. l, to free the secondary latch plate 59 from restraining engagement by that roller. These movements occur as bumpers B successively depart from engagement with the actuator rollers 83 at multiple phase signaling unit 58. That is, no further entry of a carrier into branch track 13 is permitted until these two successive indexings of the latch roller 67 have been accomplished, even though the individual advancing bumpers B are set to initiate, and do initate, signals at the advance unit 42. In each instance, though the primary latch roller 37 responds to such a signal, it then returns to its position for latching engagement with abutment 33.

In this, the lost motion connection of the tongue 15 to its secondary lever 25 (with which the latch rollers 37, 67 coact) insures that the abutment 33 will be swung clockwise sufficiently in thus resetting, to enable roller 37 to resume latching position. Similarly, the possibility of an undesired resetting movement of the tongue by a carrier proceeding unswitched or straight-through is pre vented.

The invention provides a device insuring that there shall always be two work-transporting carriers available at the accumulating station 58, further work carriers being automatically switched to replenish the same; and that so long as the required number are present no additional switching will take place. In this respect, the present invention is a refinement over the system shown and described in the copending Klamp application, identified above, although operating upon the same general principle of a phased, wholly mechanical dual control of a switch tongue by plural mechanical latch devices. A fool-proof, multiple choke control of the switch is obtained, with no possibility of jamming, or of failure to switch a needed carrier which is set to initiate switching.

What we claim as our invention is:

l. A conveyer and switch mechanism to control the selective travel of objects through a switch zone, comprising rail means acting on said objects to guide the same to and from said switch zone for selective switching at said zone, a switch at said zone movable between positions for switching and non-switching action on said objects, a first control element movable between first and second positions to respectively hold said switch in a non-switching position and to release the same for movement to a switching position, a first signal device operatively connected to said control element and actuable by objects approaching said switch to move said element to said second position, a second movable control element coacting with said first element in the control of said switch, said switch having a portion engageable by said second control element in two different switch holding positions of the latter in which said second control element holds the switch in non-switching position, a second signal device actuable by switched objects, means operatively connecting said second signal device with said second control element to move the latter to and from a switch release position, in which said second control element permits movement of the switch to switching position, and said two holding positions, and means moving said switch to switching position upon movement of both control elements to release position.

2. A conveyor and switch mechanism to control the selective travel of objects through a switch zone, comprising rail means acting on said objects to guide the same to and from said switch zone for selective switching at said zone, a switch at said zone movable between positions for switching and non-switching action on said objects, a first control element movable between first and second positions to respectively hold said switch in a non-switching position and to release the same for movement to a switching position, a first signal device mechanically connected to said control element and actuable by objects approaching said switch to move said element to said second position, a second movable control element coacting with said first element in the control of said switch, said switch having a portion engageable by said second control element in two different switch holding positions of the latter in which said second control element holds the switch in non-switching position, a second signal device mechanically actuable by switched objects, means mechanically connecting said second signal device with said second control element to move the latter to and from a switch release position, in which said second control element permits movement of the switch to switching position, and said two holding positions, and means moving said switch to switching position upon movement of both control elements to release position.

3. A conveyor and switch mechanism to control the selective travel of objects through a switch zone, comprising rail means acting on said objects to guide the same to and from said switch zone for selective switching at said zone, a switch at said zone movable between positions for switching and non-switching action on said objects, a first control element movable between first and second positions to respectively hold said switch in a nonswitching position and to release the same for movement to a switching position, a first signal device operatively connected to said control element and actuable by objects approaching said switch to move said element to said second position, a second movable control element coacting with said first element in the control of said switch, said switch having a portion engageable by said second control element in two ditierent switch holding positions of the latter in which said second control element holds the switch in non-switching position, a second signal device actuable by switched objects, means operatively connecting said second signal device with said second control element to move the latter to and from a switch release position, in which said second control element permits movement of the switch to switching position, and said two holding positions, said second signal device including units releasably engaged and actuated successively by switched objects to move said second control element between switch holding and release positions, and means moving said switch to switching position upon movement of both control elements to release position.

4. A conveyor and switch mechanism to control the selective travel of objects through a switch zone, comprising rail means acting on said objects to guide the same to and from said switch zone for selective switching at said zone, a switch at said zone movable between positions for switching and non-switching action on said objects, a first control element movable between first and second positions to respectively hold said switch in a non-switching position and to release the same for movement to a switching position, a first signal device mechanically connected to said control element and actuable by objects approaching said switch to move said element to said second position, a second movable control element coacting with said first element in the control of said switch, said switch having a portion engageable by said second control element in two dififerent switch holding positions of the latter in whichsaid second control element holds the switch in non-switching position, a second signal device mechanically actuable by switched objects, means mechanically connecting said second signal device with said second control element to move the latter to and from a switch release position, in which said second control element permits movement of the switch to switching position, and said two holding positions, said second signal device including units releasably engaged and actuated successively by switched objects to move said second control element between switch holding and release positions, and means moving said switch to switching position upon movement of both control elements to release position.

5. A conveyor and switch mechanism to control the selective travel of objects through a switch zone, comprising rail means acting on said objects to guide the same to and from said switch zone for selective switching at said zone, a switch at said zone movable between positions for switching and non-switching action on said objects, a first control element movable between first and second positions to respectively hold said switch in a non-switching position and to release the same for movement to a switching position, a first signal device mechanically connected to said control element and actuable by objects approaching said switch to move said element to said second position, a second movable control element coacting with said first element in the control of said switch, said switch having a portion engageable by said second control element in two different switch holding positions of the latter in which said second control element holds the switch in non-switching position, a second signal device mechanically actuable by switched objects, means mechanically connecting said second signal device with said second control element to move the latter to and from a switch release position, in which said second control element permits movement of the switch to switching position, and said two holding positions, said second signal device including units releasably engaged and actuated successively by switched objects to move said second control element between switch holding and release positions, and means moving said switch to switching position upon movement of both control elements to release position, said respective signal units including means acting upon simultaneous disengagement from a plurality of objects to move said second control element to a further switch release position.

6. A conveyor and switch mechanism to control'the selective travel of objects through a switch zone, comprising rail means acting on said'objects to guide the same to and from said switch zone for selective switching at said zone, a switch at said zone movable between positions for switching and non-switching action on said objects and provided with a control extension, said extension being connected to said switch by a resiliently biased, lost motion connection, a first control element movable to and from position relative to said switch extension t6 hold said switch and extension from movement to switching position, a first signal device actuable by objects approaching said switch and mechanically connected with said control element to move the latter out of switch holding position in response to actuation, a second latch control element movable into and out of holding position relative to said switch extension, said extension having a holding portion engageable by said second control element in two different switch holding positions of the latter, a second signal device releasably engageable with and actuable by switched objects, means mechanically connecting said second signal device with said second control element for operation by the latter in response to actuation of said second signal device by objects, and means moving said switch to switching position upon movement of said control elements to release position.

7. A conveyor and switch mechanism to control the selective travel of objects through a switch zone, comprising rail means acting on said objects to guide the same to and from said switch zone for selective switching at said zone, a switch at said zone movable between positions for switching and non-switching action on said objects, a first control element movable to and from position relative to said switch to hold said switch from movement to switching position, a first signal device actuable by objects approaching said switch and mechanically connected with said control element to move the latter out of switch holding position in response to actuation, a second latch control element provided with an anti-friction roller and movable into and out of holding position relative to said switch, said switch having a holding sur,

face engageable by said roller in two diiferent switch holding positions of the latter, a second signal device releasably engageable with and actuable by switched objects, means mechanically connecting said second signal device with said second control element for operation by the latter in response to actuation of said second signal device by objects, and means moving said switch to switching position upon movement of said control elements to release position.

8. A conveyor and switch mechanism to control the selective travel of objects through a switch zone, comprising rail means acting on said objects to guide the same to and from said switch zone for selective switching at said zone, a switch at said zone movable between positions for switching and non-switching action on said objects and provided with a control extension, said extension being connected to said switch by a resiliently biased, lost motion connection, a first control element movable to and from position relative to said switch extension to hold said switch and extension from movement to switching position, a first signal device actuable by objects approaching said switch and mechanically connected with said control element to move the latter out of switch holding position in response to actuation, a second latch control element provided with an anti-friction roller and movable into and out of holding position relative to said switch extension, said extension having a holding surface engageable by said roller in two difierent switch holding positions of the latter, a second signal device releasably engageable with and actuable by switched objects, means mechanically connecting said second signal device with said second control element for operation by the latter in response to actuation of said second signal device by objects, and means moving said switch to switching posi tion upon movement of said control elements to release position.

9. A conveyor and switch mechanism to control the selective travel of objects through a switch zone, comprising rail means acting on said objects to guide the same to and from said switch zone for selective switching at said zone, a switch at said zone movable between posi- I tions for switching and non-switching action on said objects and provided with acontrol extension, said extension being connected to said switch by a resiliently biased,

element in two different switch holding positions of thelatter, a second signal device releasably engageable with and actuable by switched objects, means mechanically connecting said second signal device with said second control element for operation by the latter in response to actuation of said second signal device by objects, and means moving said switch to switching position upon movement of said control elements to release position, said second signal device comprising units disengageable from successive switched objects to position said second control element in two switch release positions.

10. A conveyor and switch mechanism to control the selective travel of objects through a switch zone, comprising rail means acting on said objects to guide the same to and from said switch zone for selective switching at said zone, a switch at said zone movable between positions for switching and non-switching action on said objects, a first control element movable to and from position relative to said switch to hold said switch from movement to switching position, a first signal device actuable by objects approaching said switch and mechanically connected with said control element to move the latter out of switch holding position in response to actuation, a second latch control element provided with an antifriction roller and movable into and out of holding position relative to said switch, said switch having a holding surface engageable by said roller in two different switch holding positions of the latter, a second signal device releasably engageable with and actuable by switched ob jects, means mechanically connecting said second signal device with said second control element for operation by the latter in reponse to actuation of said second signal device by objects, and means moving said switch to switching position upon movement of said control elements to release position, said second signal device comprising units disengageable from successive switched objects to position said second control element in two switch release positions.

11. A conveyor and switch mechanism to control the selective travel of objects through a switch zone, comprising rail means acting on said objects to guide the same to and from said switch zone for selective switching at said zone, a switch at said zone movable between positions for switching and non-switching action on said objects and provided with a control extension, said extension being connected to said switch by a resiliently biased, lost motion connection, a first control element movable to and from position relative to said switch extension to hold said switch and extension from movement to switching position, a first signal device actuable by objects approaching said switch and mechanically connected with said control element to move the latter out of switch holding position in response to actuation, a second latch control element provided with an anti-friction roller and movable into and out of holding position relative to said switch extension, said extension having a holding surface engageable by said roller in two different switch holding positions of the latter, a second signal device releasably engageable with and actuable by switched objects, means mechanically connecting said second signal device with said second control element for operation by the latter in response to actuation of said second signal device by objects, and means moving said switch to switching position upon movement oi said control elements to release position, said secondsignal device lcomprising units disengageable from successive switched objects to position said second control element in two switch release positions.

12. Apparatus 'to control the selectively diverted travel of objects from a first station through a switch zone, and the maintenance of an accumulation of diverted objects at an accumulator station, comprising rail means to guide said objects to and from said switch zone, a signal unit adjacent said first station mechanically actuable by selected objects passing the same, a switch controlling the diversion of objects through said switch zone, a first control element for said switch mechanically connected to said signal unit, said element being responsive to an actuation of the said signal unit to condition said switch for said diversion of an object, a plural phase signal mechanism positioned adjacent said accumulator station and repeatedly actuable mechanically in a given signaling operation of said mechanism by diverted objects reaching the same, and a switch control mechanism mechanically connected to said signal mechanism and operable in two steps in response to a plural phase signaling operation of the latter to overrule the conditioning of said switch by said first control element.

13. Apparatus to control the selectively diverted travel of objects from a first station through a switch zone, and the maintenance of an accumulation of diverted objects at an accumulator station, comprising rail means to guide said objects to and from said switch zone, a signal unit adjacent said first station mechanically actuable by selected objects passing the same, a switch controlling the diversion of objects through said switch zone, a first control element for said switch mechanically connected to said signal unit, said element being responsive to an actuation of the said signal unit to condition said switch for said diversion of an object, a plural phase signal mechanism positioned adjacent said accumulator station and repeatedly actuable mechanically in a given signaling operation of said mechanism by diverted objects reaching the same, and a switch control mechanism mechanically connected to said signal mechanism and operable in two steps in response to a plural phase signaling operation of the latter to overrule the conditioning of said switch by said first control element, said control mechanism comprising a second element having plural positions of holding engagement with said switch in which it overrules movement of the latter to diverting position.

14. Apparatus to control the selectively diverted travel of objects from a first station through a switch zone, and the maintenance of an accumulation of diverted objects at an accumulator station, comprising rail means to guide said objects to and from said switch zone, a signal unit adjacent said first station mechanically actuable by selected objects passing the same, a switch controlling the diversion of objects through said switch zone, a first control element for said switch mechanically connected to said signal unit, said element being responsive to an actuation of the said signal unit to condition said switch for said diversion of an object, a plural phase signal mechanism positioned adjacent said accumulator station and repeatedly actuable mechanically in a given signaling operation of said mechanism by diverted objects reaching the same, and a switch control mechanism mechanically connected to said signal mechanism and operable in two steps in response to a plural phase signaling operation of the latter to overrule the conditioning of said switch by said first control element, said control mechanism comprising a second element having plural positions of holding engagement with said switch in which it overrules movement of the latter to diverting position, said signal mechanism comprising plural signal units operatively connected by an articulating linkage to said second control element to actuate the latter only in response to a plurality of objects reaching said accumulator station,

15. A conveyor and switch mechanism to control the selective travel of objects through a switch zone, comprising rail means acting on said objects to guide the same to and from said switch zone for selective switching at said zone, a switch at said zone movable between positions for switching and non-switching action on said objects, a first control element movable between positions in which it controls movement of said switch as between a non-switching position and a switching position, a first signal device operatively connected to said control element and actuable by objects approaching said switch to move said element to a position in which movement of said switch to switching position may result, a second movable control element coacting with said first element in the control of said switch, said switch having a portion 14 engageable by said second control element in two dilferent control positions of the latter preventing movement of the switch to said switching position, a second signal device actuable by switched objects, and means operatively connecting said second signal device with said second control element to move the latter to and from both of said control positions.

References Cited in the file of this patent UNITED STATES PATENTS 1,213,317 Weller et al. Jan. 23, 1917 1,625,501 Robertson Apr. 19, 1927 2,714,355 Benson Aug. 2, 1955 

